The use of sputtering in order to deposit coatings on substrates is known in the art. For example, and without limitation, see U.S. Pat. Nos. 5,403,458; 5,317,006; 5,527,439; 5,591,314; 5,262,032; and 5,284,564. Briefly, sputter coating is an electric-discharge-type process which is conducted in a vacuum chamber in the presence of at least one gas. Typically, a sputtering apparatus includes a vacuum chamber, a power source, an anode, and one or more cathode targets which include material used to create a coating on an adjacent substrate. The target may include an outer tube enclosing a magnet bar assembly including and an associated inner magnet bar support tube. More specifically, in certain known arrangements, the one or more magnet bars are secured to the underside of the support tube along substantially the length of the support tube.
When an electrical potential is applied to the cathode target, the gas forms a plasma which bombards the target causing particles of the material from the target to leave the exterior surface of the outer target tube. These particles fall onto the substrate to thereby form the coating thereon. The outer target tube typically rotates about the stationary magnets supported by the inner support tube so that particles are “sputtered” uniformly from the entire periphery of the target tube as it rotates past the fixed magnet bar.